Apparatus for reheating steam for use in turbines



Aug. 18 1931.

L. J. MARSHALL.

APPARATUS FOR- REHEATING STEAM FOR USE IN TURBINES Filed May 51, 1928 W/SUPERHEATER W/SUPERHEATER g 30mm BOILER 15 5 W J I REHEATER -RHEAT/? 6 TURIB/NE 7 '1 NVENTOR W WM Patented Aug. 18, 1931 UE'FEZD STATES PATENT OFFICE,

LEONARD J". MARSHALL, OF WESTWOOD, NEW JERSEY, ASSIGNOR TO INTERNATIONAL COMBUSTION ENGINEERING CORPORATION, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE APPARATUS non REHEATING STEAM roa'osn In renames Y Application filed May a1, 1928. Serial 1%. 281,825.

This invention relates to improvements in the art of reheating steam in boilers and particularly to reheating interstage steam of prime movers.

In this art it is customary to take steam for .a turbine from two or more boilers and to return steam from a certain stage of the turbine, or from the exhaust of a high pressure turbine, to reheaters located in the path of the gases in one or all of the severalboilers cooperating with the turbines, or to separately heated reheaters, and from thence to pass the reheated steam to the succeeding stage of the turbine or to the low pressure turbine which cooperated with the high pressure turbine.

In order that this may be done in a manner to ensure low maintenance and to obviate possible damage to the turbine, it is :important that an even temperature of steam obtains in the turbine .at all ratings of the boiler.

In the case of two boilers with reheaters in each boiler, it has heretofore been the practice, in order to meet the above conditions, to connect the reheaters in parallel and to provide means for dividing the steam passing to the reheaters between the boilers in proportion to the load being carried by each boiler. Apparatus known for this purpose comprises thermostatically controlled valve devices of a complicated nature.

I propose to obviate the operating difiiculties of maintaining a constant reheat by means of a reheater in the path of the gases in one of the several boilers employed, or in a separately fired reheater, or by employing valve devices of any description for the puroses above set forth, and it is, therefore, one of the objects of my invention to provide an apparatus for reheating steam for turbines or engines by means of which the degree of heat leaving the reheaters of two or more boilers supplying steam to the units is maintained substantially uniform, although the ratings of the individual boilers may vary.

More specifically stated, it is an object of my invention in apparatus of the class described to serially connect the reheaters of two or more boilers so that a substantially uniform degree of s'uperheat leaving the reheaters is obtained boilers.

It is to be understood that fluids other than steam may be reheated by my method and for other purposes than that described herein. The method may be used in cooperation with either the convection, radiant heat or other type of superheater and any combination of them.

How the foregoing, together with such other objects and advantages as may hereinafter appear, or are incident to my invention are realized is illustrated in preferred form in the accompanying drawing, wherein The figure'isv a diagrammatic view illustrating my invention. In the drawing 1 have diagrammatically shown two high pressure. boilers at A and B, say, for example, a boiler having some pressure above 450 lbs, and a two-stage turbine at C. The boiler A is'equipped with a superheater Qand a reheater 3, and the boiler B is equipped with a superheatert and a reheater 5. The turbine C- is divided into a high pressure end 6 and a low pressure end 7 in a well known manner, or the two ends may be separate units as is often the case.

Steam from the superheater 2 of the boiler A and from the superheater at of the boiler B leads in parallel by means of steam lines 8 and 9, into the main steam line 10, which, in turn, leads to the high pressure end 6 of the an. bine C. After the steamkhas expanded in this end to the stage where resuperheating becomes desirable, it is led off from this stage of the turbine by means of a pipe line 11 and is passed serially through the reheaters of the boilers and returned to the following stage of the turbine. In this instance the pipe 11 is connected to the reheater 5 of the boiler-B, and this reheater is connected-in series with the reheater 3 of the boiler A. A pipeline 12 connects the reheater 3 with the following stage in the low pressure end 7 of the turbine.

at. all ratings of the stant total output of all boilers, should one boiler work at a higher or lower rating than the others, the super-heaters will likewise work at proportionately higher or lower ratings, andhence adjustment of the reheaters to the relative decrease or increase in ratings of their boilers is effected, and the sum of the superheats of the individual reheaters, owing to their serial connection, will Y remain substantially constant. 7

From the foregoing it will be seen that 1 have provided a Very simple and effective apparatus for reheating steam for use in turbines in which two or more boilers are employed, by means of which an even temperature of reheated steam obtains in the turbine at all ratings of the boilers without the necessity of employing complicated mechanisms for distributing the steam to be reheated to the boilers proportionately to the amount of work being done by the boilers.

I claim 1. In combination, a plurality of boilers, a multiple stage prime mover, means for leading high pressure fluid from said boilers to the high pressure stage of said prime mover, a fluid reheater in each of different boilers, said reheaters being connected in series, means for leading the fluid from a stage of the prime mover to said serially connected reheaters, and means for leading the reheated fluid from said serially connected reheaters to the stage following said stage. 7

2. In combination, a plurality of boilers, each one of which is provided with a superheater, a multistage turbine, a main fluid line leading to the high pressure stage of the turbine, means for supplying working fluid to said main steam line from said superheaters in parallel, a reheater for each of different boilers, means for connecting said reheaters in series, means for leading the fluid from a lower stage of the turbine to said reheaters, and means for leading reheated fluid from said reheaters to the stage following said lower stage. 7

In testimony whereof I have hereunto slgned my name.

LEONARD J. MARSHALL. i 

